Introduction to Phylum Arthropoda: 1.3 Million Species

What percentage of all described animal species do arthropods represent?

• 20-25%

• 50-60%

• 80-85%

• Less than 10%

Which of the following accurately describes arthropods?

• Radially symmetrical, diploblastic, acoelomates

• Bilaterally symmetrical, triploblastic, coelomates

• Asymmetrical, diploblastic, pseudocoelomates

• Bilaterally symmetrical, triploblastic, acoelomates

What type of circulatory system do arthropods possess?

• Closed circulatory system with a ventral heart

• Open circulatory system with a dorsal contractile heart

• No circulatory system, relying on diffusion

• A network of closed vessels without a central pump

What is the most distinguishing characteristic that differentiates arthropods from other animal phyla?

• Their complex social organization

• Their diverse respiratory systems

• Their jointed appendages

• Their cuticular exoskeleton

What is the outer covering of an arthropod's exoskeleton called?

• Epidermis

• Procuticle

• Cuticle

• Endocuticle

Why must arthropods shed their old exoskeleton?

• To change their color for camouflage.

• To grow in size.

• To reproduce.

• To repair damaged body parts.

How do most terrestrial arthropods breathe?

• Through their mouths.

• Through their skin.

• Through spiracles.

• Through gills.

What is a key advantage of metamorphosis in arthropods?

• It allows them to live longer.

• It helps them avoid competition between adults and juveniles.

• It makes them more attractive to mates.

• It provides better protection from predators.